Ronnie O'Sullivan overcame early nerves to cruise ahead of Dominic Dale 7-2 in a fascinating start to their first-round World Championship clash.
The three-time world champion, who had threatened to withdraw from the tournament, opened up a two-frame lead in a nervy start before Dale levelled.
O'Sullivan's fireworks duly arrived as he won four successive frames, twice narrowly missing out on a maximum 147.
He then racked up his 100th Crucible ton to help build a five-frame lead.
The pair will resume their battles on Tuesday at 1430 BST.
The atmosphere at the Crucible was electric as the former number one entered the arena to face the entertaining Welshman, who had declared confidently last week that if he played at his best then O'Sullivan was beatable.
It was a big statement for a 39-year-old playing on the sport's biggest stage for the first time in seven years and more of a reflection on the recent slide in form of O'Sullivan.
However, having attempted to pull out of the World Championship less than two weeks to go, only to change his mind a day later, there was an element of relief that the 'Rocket' even turned up.
And despite his slow start, there was much to admire from the man who arrived at Sheffield on the back of four first-round defeats in ranking events and without a single major win since clinching the Premier League title last November.
Chigwell's top cueman, eyeing his fourth world crown 10 years after winning his first, edged an error-ridden opening frame and looked to have finally settled when he was eyeing a maximum 147 before running out of position after sinking nine reds and eight blacks.
A 78, though, was enough to double the lead. But Dale, winner of two major titles with the Grand Prix in 1997 and Shanghai Masters four years ago, is an experienced campaigner and although an error on 47 gifted O'Sullivan a reprieve, the Vienna-based star stayed cool to deservedly pull one back.
With O'Sullivan slumped into his chair, Dale roared on and levelled the score at 2-2 to give his Welsh fans plenty to cheer about at the mini-break and he should have even made it three in a row.
A smooth run of 47 had him in the driving seat, but a fluffed red had O'Sullivan jumping to the baize and a clearance including a tricky last red down the rails handed him back the lead.
The scrappiness continued with O'Sullivan seizing a two-frame advantage after clearing with a 46, but frame seven was the moment which kick-started a breath-taking spell of O'Sullivan snooker to get the crowd on the edge of their seats.
With 12 reds 12 blacks already in the pockets, the maximum looked assured but a tough red down the cushion proved the stumbling block to deny O'Sullivan a fourth Crucible 147.
His cueing arm was now in full flow and a stunning 113 and a 74 secured his fifth successive frame and wrap up a good afternoon's work for O'Sullivan as Dale was left rueing a number of wasted opportunities earlier in the match.